From owner-freebsd-questions@FreeBSD.ORG Wed Sep 12 02:19:27 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 50334106564A for ; Wed, 12 Sep 2012 02:19:27 +0000 (UTC) (envelope-from paul@kraus-haus.org) Received: from mail-oa0-f54.google.com (mail-oa0-f54.google.com [209.85.219.54]) by mx1.freebsd.org (Postfix) with ESMTP id 0E87B8FC0A for ; Wed, 12 Sep 2012 02:19:26 +0000 (UTC) Received: by oagm1 with SMTP id m1so853964oag.13 for ; Tue, 11 Sep 2012 19:19:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:x-gm-message-state; bh=EzEP7UqYpDaaZsuSPsKAC7HB8VhfV81f4bMVPkoh8jw=; b=M048zptz7Di+df5bkcp5ZPrsUbn9x/j0etnS1lzFj0hqqv18ixduaRqreEWnNO3lHr XsKgxihZ4vsg8zu8mes4UcNBLVwqelihU3SeK9PObVdSU9Ug9luUnSmYZQYUGR3JLfCF op559Kpe0i12QRXijAPdCIdwMZSNyL22moAEpTaVkRywWuH8x26Bg64qHxj7p2r3pP9F yGnXKzeAuAlcvUVwtogP1bhrbH8r4/kTVG+OqPJFs3L6IDxGDKCNvFlQ0j+YELm2Whxa 3pTcupAbAV2DMWn2BdVJ+o0rZ1e4DuknKltuT91ibwcpmUOodG7zjrOpkSbZYR7j/vYc zy2Q== MIME-Version: 1.0 Received: by 10.182.154.70 with SMTP id vm6mr20971416obb.50.1347416366135; Tue, 11 Sep 2012 19:19:26 -0700 (PDT) Received: by 10.60.147.138 with HTTP; Tue, 11 Sep 2012 19:19:26 -0700 (PDT) In-Reply-To: <20120912020347.GC10496@ethic.thought.org> References: <20120911213804.GA9817@ethic.thought.org> <20120912011443.5df17cf2.freebsd@edvax.de> <20120912002408.GA10496@ethic.thought.org> <20120912024854.1a79d0b3.freebsd@edvax.de> <20120912020347.GC10496@ethic.thought.org> Date: Tue, 11 Sep 2012 22:19:26 -0400 Message-ID: From: Paul Kraus To: FreeBSD Mailing List Content-Type: text/plain; charset=ISO-8859-1 X-Gm-Message-State: ALoCoQlBQC8qqdrV7Av5DzEjsXGg6t2xB6t1RYwMBGnZ4P4V4dpAn6svguDnUlDvK3xVc4gCr5+2 Subject: Re: cksum entire dir?? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Sep 2012 02:19:27 -0000 On Tue, Sep 11, 2012 at 10:03 PM, Gary Kline wrote: > I'm not concerned about a file having been changed, just whether > > % cp -rp /home/klinebak/foodir /home/kline/ > > is 100% reliable. down to the bit! If "cp" is not reliable (down to the bit), then you have much bigger problems. On the other hand, hard drives do have uncorrectable errors and they report the read operation as valid even though they returned bad data. That is part of why ZFS was created and ported to FreeBSD, it checksums the data so a bad bit coming from a drive does not corrupt a file. -- {--------1---------2---------3---------4---------5---------6---------7---------} Paul Kraus -> Principal Consultant, Business Information Technology Systems -> Deputy Technical Director, LoneStarCon 3 (http://lonestarcon3.org/) -> Sound Coordinator, Schenectady Light Opera Company ( http://www.sloctheater.org/ ) -> Technical Advisor, Troy Civic Theatre Company -> Technical Advisor, RPI Players